Apparatus for drilling boreholes



L. F. SMITH APPARATUS FOR DRILLING BORE HOLES Filed Jan. 9, 1945 May 9, 1950 lllll' Patented May 9, 1950 UNITED STATES PATENT OFFICE APPARATUS FOR DRILLING BOREHOLES Application January 9, 1945, Serial N0. 571,987

2 Claims.

This invention relates to an apparatus for drilling bore holes.

An object of the invention is to provide apparatus of the character described for drilling bore holes in the earth formation and which embodies a tubular drilling string, or stem, having a drill secured on the lower end thereof with a sample recovery tube leading from the drill upwardly through the stem to the ground surface and spaced inwardly from the drill stem thus providing a channel between the stem and tube through which the drilling uid may be forced downwardly to the drill, said drill being provided with outlet ports from said channel to the formation at the bottom of the bore; and said apparatus being provided with means for controlling the return flow of the drilling fluid either upwardly through the bore outside of the drill stem or upwardly through the sample recovery tube to wash away the drill cuttings and to return samples of the formation through the tube to the ground surface for inspection.

In drilling ordinary formation where samples are not desired the drilling fluid may be returned back up through the bore around the drill stem and carried vofi to the slush pit but when it is desired to recover and inspect samples of the strata being drilled the construction is such that the drilling fluid may be returned up through the sample recovery tube so as to carry the samples up through said tube where they may be recovered and inspected.

The apparatus has been primarily designed for drilling, and recovering samples of, hard formation although it may be used for ordinary drilling purposes.

The invention also embodies a novel method for controlling the return flow of the drilling fluid so as to carry off the drill cuttings or so as to enable the operator to recover samples of the formation for inspection when desired.

With the above and other objects in view the invention has particular relation to certain novel features of construction, operation and arrangement of parts and to a novel method, examples of which are given in this specification and illustrated in the accompanying drawings, wherein- Figure 1 shows a side elevation, partly in section, of the drilling apparatus as in operation; and

Figure 2 shows a cross, sectional View taken on the line 2--2 of Figure 1.

Referring now more particularly to the drawings wherein like numerals of reference designate similar parts in each of the gures, the nu- 2 meral I designates a tubular drill stem. This stem is made up of a plurality of sections which may be connected by coarse threads such as 2 so that the sections may be quickly connected and disconnected.

Attached to the lower end of the stem there is a drill 3. A diamond core drill is shown in the illustration. At its lower end this drill is reduced in its internal diameter forming the inside, annular, upwardly facing shoulder 4. The lower end of the drill is also provided with one or more outlet ducts 5 through which drilling fluid may reach the bottom of the bore.

Supported on the shoulder' Il and extending upwardly through the drill stem there is a sample recovery tube 6 which is spaced inwardly from the drill stem thus providing a channel 'I for the downward flow of the drilling fluid. The duct 5 is connected into this channel.

The numeral 8 designates the well casing which is set in the well bore and which is spaced outwardly from the drill stem to provide a return channel 9 for the drilling uid.

The tube 6 is held centered relative to the drill stem by means of suitable spacers I IJ, and is composed of sections.

A casing head I I is secured to the upper end of the casing 8 and surrounds the drill stem. A seal is provided between the upper end 0i the casing head and the drill stem. Any selected type of seal may be used, an ordinary stuing box I2 being shown.

The casing head has a flow line I3 connected into it beneath the seal and this flow line is equipped with a conventional type of shutoff Valve I4.

The flow line may lead to the ordinary pit which is usually provided to receive the returning drilling uid.

Connected to the upper end of the drill stem I, by means of coarse threads I5, there is a swivel designated generally by the numeral I 6. This swivel comprises a tubular rotatable swivel body I1, surrounding which is the stationary jacket I8 which is provided with an inlet I9 through which the drilling fluid is forced by a suitable pump.

Between the body I'I and the upper and lower ends of the stationary jacket I8 there are sealring assemblies 2B and 2I, the latter of which is supported on the external, annular shoulder 22 of the rotatable body I'I and the former of which is maintained in place by the retaining nuts 23 screwed onto the upper end of the body I'I. The swivel may be supported by a suitable bail 24.

The upper end of the sample recovery tube 6 extends up through the swivel and fits closely through the body I'I.

The body I'I of the swivel has an inside annular channel 25 therearound which is enclosed by the tube 6 thus forming a chamber and the body II has an inlet port 26 through which the drilling fluid may enter said chamber. This drilling fluid iiows from the chamber downwardly through one or more ducts 2 and on down through the channel 'I and out through the duct 5 to the formation being drilled. This drilling fluid is under pressure and will be returned up around the drill stern and out through the ow line I3 or up through the sample recovery tube 6 depending upon whether the valve I4 is opened or closed. The valve I4 may be partly opened so that part of the drilling fluid will be returned up around the drill stem and out through the flow line I3 and partly up through the tube 6. This return ow of the drilling iluid is under the complete control of the operator through the instrumentality of the valve I4.

During ordinary drilling operations where sample recovery is not desired the valve Ie may be completely opened and in such event the major portion of the drilling fluid will be returned up around the drill stern and carried off through the flow line IS. However, should a recovery of a sample be desired the valve It may be entirely or partly ciosed so that a sufficient portion of the drilling iiuid will be caused to return up through the sample recovery tube to iloat out the desired samples through said tube to the ground surface for inspection. The drilling iluid with the samples therein may be recovered from the upper end of the tube 5 in any preferred manner.

It is to be understood that the drilling will be carried on by the rotary process. The drill stem may be rotated .'by any suitable type of rotary drilling equipment connected thereto above the casing head.

What I claim is:

1. Apparatus for drilling bore holes comprising, a casing set in the bore, a rotatable tubular drill stem extending into the bore through the casing and spaced therefrom to provide a return channel, a seal between the upper end of the casing and the stern, an outflow pipe leading from said channel beneath the seal, a valve controlling said outflow pipe, a core forming drill on the lower end of the stem having a core receiving inlet and an inside, upwardly facing, shoulder, a sample return tube within and spaced from the stem to form a supply channel for drilling fluid around the tube, said tube being supported on the shoulder of the drill, said drill having a duct leading downwardly therethrough from the supply channel through which drilling fluid may be supplied to the formation being drilled, means for supplying a drilling fluid under pressure to said supply channel, said valve forming means for controlling the iiow of said iluid through the return channel whereby the velocity of the fluid returning through said tube may be Varied.

2. Apparatus of the character described comprising a tubular rotatable drill stem, a swivel connected to the upper end of the stem and comprising, a tubular swivel body having an inlet port and an inside annular channel connected with said port, a stationary jacket around the body and sealed therewith above and beneath said port, an inlet through the jacket for the inlet of drilling fluid into said channel, said body having upper ducts leading downwardly from the channel into the stern, an annular drill on the lower end of the stern having a Central core inlet and having a duct leading downwardly through the drill, a sample receiving tube supported on the drill and aligned with the core inlet and spaced inwardly from the duct through the drill and thus forming a channel for drilling iluid between the stem and tube, which channel communicates with said upper and lower ducts, said apparatus having a return channel outside of the stem and means for controlling the flow of the returning fluid through the return channel whereby the return of fluid through the tube may be controlled.

LOUIE F. SMITH.

REFERENCES CITED The following references are oi record in the file of this patent:

UNITED STATES PATENTS 

